#include <tool.h>
#define ZEROPAD 1               // Pad with zero
#define SIGN    2               // Unsigned/signed long
#define PLUS    4               // Show plus
#define SPACE   8               // Space if plus
#define LEFT    16              // Left justified
#define SPECIAL 32              // 0x
#define LARGE   64              // Use 'ABCDEF' instead of 'abcdef'

#define is_digit(c) ((c) >= '0' && (c) <= '9')

static char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
static char *upper_digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

static int skip_atoi(const char **s){
  int i = 0;
  while (is_digit(**s)) i = i*10 + *((*s)++) - '0';
  return i;
}

static char *number(char *str, long num, int base, int size, int precision, int type){
  char c, sign, tmp[66];
  char *dig = digits;
  int i;

  if (type & LARGE)  dig = upper_digits;
  if (type & LEFT) type &= ~ZEROPAD;
  if (base < 2 || base > 36) return 0;
 
  c = (type & ZEROPAD) ? '0' : ' ';
  sign = 0;
  if (type & SIGN){
    if (num < 0){
      sign = '-';
      num = -num;
      size--;
    }
    else if (type & PLUS){
      sign = '+';
      size--;
    }
    else if (type & SPACE){
      sign = ' ';
      size--;
    }
  }

  if (type & SPECIAL){
    if (base == 16)
      size -= 2;
    else if (base == 8)
      size--;
  }

  i = 0;

  if (num == 0)
    tmp[i++] = '0';
  else{
    while (num != 0){
      tmp[i++] = dig[((unsigned long) num) % (unsigned) base];
      num = ((unsigned long) num) / (unsigned) base;
    }
  }

  if (i > precision) precision = i;
  size -= precision;
  if (!(type & (ZEROPAD | LEFT))) while (size-- > 0) *str++ = ' ';
  if (sign) *str++ = sign;
 
  if (type & SPECIAL){
    if (base == 8)
      *str++ = '0';
    else if (base == 16){
      *str++ = '0';
      *str++ = digits[33];
    }
  }

  if (!(type & LEFT)) while (size-- > 0) *str++ = c;
  while (i < precision--) *str++ = '0';
  while (i-- > 0) *str++ = tmp[i];
  while (size-- > 0) *str++ = ' ';

  return str;
}

static char *eaddr(char *str, unsigned char *addr, int size, int precision, int type){
  char tmp[24];
  char *dig = digits;
  int i, len;

  if (type & LARGE)  dig = upper_digits;
  len = 0;
  for (i = 0; i < 6; i++){
    if (i != 0) tmp[len++] = ':';
    tmp[len++] = dig[addr[i] >> 4];
    tmp[len++] = dig[addr[i] & 0x0F];
  }

  if (!(type & LEFT)) while (len < size--) *str++ = ' ';
  for (i = 0; i < len; ++i) *str++ = tmp[i];
  while (len < size--) *str++ = ' ';

  return str;
}

static char *iaddr(char *str, unsigned char *addr, int size, int precision, int type){
  char tmp[24];
  int i, n, len;

  len = 0;
  for (i = 0; i < 4; i++){
    if (i != 0) tmp[len++] = '.';
    n = addr[i];
   
    if (n == 0)
      tmp[len++] = digits[0];
    else{
      if (n >= 100){
        tmp[len++] = digits[n / 100];
        n = n % 100;
        tmp[len++] = digits[n / 10];
        n = n % 10;
      }
      else if (n >= 10){
        tmp[len++] = digits[n / 10];
        n = n % 10;
      }

      tmp[len++] = digits[n];
    }
  }

  if (!(type & LEFT)) while (len < size--) *str++ = ' ';
  for (i = 0; i < len; ++i) *str++ = tmp[i];
  while (len < size--) *str++ = ' ';

  return str;
}
char buffer[65536];
int printf(const char *fmt, ...) {
  va_list ap;
  int n;
  va_start(ap, fmt);
  n = vsprintf(buffer, fmt, ap);
  va_end(ap);
  char *p = buffer;
  while(*p){
    putch(*p);
    p++;
  }
  return n;
}


int sprintf(char *out, const char *fmt, ...) {
  va_list ap;
  int n;
  va_start(ap, fmt);
  n = vsprintf(out, fmt, ap);
  va_end(ap);
  return n;
}

int snprintf(char *out, size_t n, const char *fmt, ...) {
  //panic("Not implemented");
  va_list ap;
  int num;
  va_start(ap, fmt);
  num = vsnprintf(out, n, fmt, ap);
  va_end(ap);
  return num;
}

int vsprintf(char *out, const char *fmt, va_list ap) {
  return vsnprintf(out, strlen(fmt), fmt, ap);
}

int vsnprintf(char *out, size_t n, const char *fmt, va_list ap) {
  int len;
  unsigned long num;
  int i, j, base;
  char *str;
  char *s;

  int flags;            // Flags to number()

  int field_width;      // Width of output field
  int precision;        // Min. # of digits for integers; max number of chars for from string
  int qualifier;        // 'h', 'l', or 'L' for integer fields

  for (j = 0, str = out; *fmt && j < n; fmt++){
    if (*fmt != '%'){
      *str++ = *fmt;
      continue;
    }
                 
    // Process flags
    flags = 0;
repeat:
    fmt++; // This also skips first '%'
    switch (*fmt){
      case '-': flags |= LEFT; goto repeat;
      case '+': flags |= PLUS; goto repeat;
      case ' ': flags |= SPACE; goto repeat;
      case '#': flags |= SPECIAL; goto repeat;
      case '0': flags |= ZEROPAD; goto repeat;
    }
         
    // Get field width
    field_width = -1;
    if (is_digit(*fmt))
      field_width = skip_atoi(&fmt);
    else if (*fmt == '*'){
      fmt++;
      field_width = va_arg(ap, int);
      if (field_width < 0){
        field_width = -field_width;
        flags |= LEFT;
      }
    }

    // Get the precision
    precision = -1;
    if (*fmt == '.'){
      ++fmt;   
      if (is_digit(*fmt))
        precision = skip_atoi(&fmt);
      else if (*fmt == '*'){
        ++fmt;
        precision = va_arg(ap, int);
      }
      if (precision < 0) precision = 0;
    }

    // Get the conversion qualifier
    qualifier = -1;
    if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L'){
      qualifier = *fmt;
      fmt++;
    }

    // Default base
    base = 10;

    switch (*fmt){
      case 'c':
        if (!(flags & LEFT)) while (--field_width > 0) *str++ = ' ';
        *str++ = (unsigned char) va_arg(ap, int);
        while (--field_width > 0) *str++ = ' ';
        continue;

      case 's':
        s = va_arg(ap, char *);
        if (!s) s = "<NULL>";
        len = strnlen(s, precision);
        if (!(flags & LEFT)) while (len < field_width--) *str++ = ' ';
        for (i = 0; i < len; ++i) *str++ = *s++;
        while (len < field_width--) *str++ = ' ';
        continue;

      case 'p':
        if (field_width == -1){
          field_width = 2 * sizeof(void *);
          flags |= ZEROPAD;
        }
        str = number(str, (unsigned long) va_arg(ap, void *), 16, field_width, precision, flags);
        continue;

      case 'n':
        if (qualifier == 'l'){
          long *ip = va_arg(ap, long *);
          *ip = (str - out);
        }
        else{
          int *ip = va_arg(ap, int *);
          *ip = (str - out);
        }
        continue;

      case 'A':
        flags |= LARGE;

      case 'a':
        if (qualifier == 'l')
          str = eaddr(str, va_arg(ap, unsigned char *), field_width, precision, flags);
        else
          str = iaddr(str, va_arg(ap, unsigned char *), field_width, precision, flags);
        continue;

      // Integer number formats - set up the flags and "break"
      case 'o':
        base = 8;
        break;

      case 'X':
        flags |= LARGE;

      case 'x':
        base = 16;
        break;

      case 'd':
      case 'i':
        flags |= SIGN;

      case 'u':
        break;

      default:
        if (*fmt != '%') *str++ = '%';
        if (*fmt)
          *str++ = *fmt;
        else
          --fmt;
        continue;
    }

    if (qualifier == 'l')
      num = va_arg(ap, unsigned long);
    else if (qualifier == 'h'){
      if (flags & SIGN)
        num = va_arg(ap, int);
      else
        num = va_arg(ap, unsigned int);
    }
    else if (flags & SIGN)
      num = va_arg(ap, int);
    else
      num = va_arg(ap, unsigned int);

    str = number(str, num, base, field_width, precision, flags);
  }

  *str = '\0';
  return str - out;
}